Incisal Overlap Research Articles

Vertical marginal gap and internal fit of virgilite-based lithium disilicate glass ceramic veneers with different preparation designs.

To evaluate and compare internal fit and marginal adaptation of conventional lithium disilicate (LDS) glass ceramics and LDS containing virgilite computer-aided design and manufacturing (CAD-CAM) blocks before and after aging. Seventy-two epoxy replicated dies from two prepared maxillary right central incisors acrylic typodont were divided into two groups of different preparation designs (n = 36): Group I, incisal butt-joint, and Group P, incisal overlap. Each group was further subdivided into two equal groups according to ceramic material (n = 18): Group E, IPS e.max CAD, and Group T, Tessera advanced lithium disilicate (ALD) CAD-CAM blocks. The replica technique was used to assess the internal fit using a stereomicroscope at 45× magnification. Laminate veneers were cemented to their corresponding epoxy dies, then the vertical marginal gap was evaluated before and after thermal cycling. Repeated measures analysis of variance (ANOVA) were used for marginal fit data and 2-way ANOVA for internal fit measurements (α = 0.05). For internal fit, there were no significant differences between tested groups. For vertical marginal gap results, two-way ANOVA showed that only aging had a significant effect on the vertical marginal gap (p<0.001), while different CAD-CAM materials and preparation designs did not affect the vertical marginal gap. The vertical marginal gap and internal fits of IPS e.max CAD and CEREC Tessera CAD for both preparation designs were comparable. Aging significantly affected the vertical marginal gap of the laminate veneers of both materials and both preparation designs; however, all were within clinically acceptable ranges before and after aging.

Effect of preparation design and scan pattern on the accuracy of intraoral scans for complete arch laminate veneers under simulated intraoral variables.

The purpose of the study was to investigate the influence of different preparation designs and scan patterns on the accuracy of intraoral scans for complete-arch maxillary laminate veneers. Three maxillary typodonts were used to obtain reference models with three different laminate veneer preparation designs: windows (W), beveled (B), and incisal overlap (IO). Reference scans were obtained with a desktop scanner. A total of 90 complete arch intraoral scans were made with an intraoral scanner (Medit i700) following three different scan patterns: straight motion (SM), zigzag motion (ZM), and combined motion (CM). Ten scans were made in each subgroup and exported as standard tessellation language (STL) files. Assessment of accuracy was conducted with a 3D software analysis program (Geomagic Control X). Each STL file was individually aligned with the reference scan using the best fit algorithm tool, and 3D differences were calculated using the root mean square (RMS) value. Two-way analysis of variance (ANOVA) followed by post hoc comparison tests were applied to analyze precision and trueness data (α = 0.05). Two-way ANOVA and post hoc comparison tests revealed significant differences among different preparation designs and scan patterns (p < 0.05). Regarding trueness, the IO when scanned with SM presented higher mean RMS than the other preparation designs (W and B) scanned with the same scanning pattern (p < 0.05). Regarding precision, the groups of W and IO presented significantly higher mean RMS than the group of B when scanned with ZM (p < 0.05). Accuracy of intraoral scans for complete-arch laminate veneers was affected by different laminate veneer preparation designs and scan patterns. Modifying scan pattern according to preparation design helps to improve scan accuracy for complete-arch laminate veneers.

A clinical case of treatment of a reverse incisal overlap

A clinical case of treatment of a reverse incisal overlap

Anterior open bite correction via molar intrusion: Diagnosis, advantages, and complications

Anterior open bite can be effectively treated nonsurgically via molar intrusion. This technique, involving the intrusion of posterior teeth using temporary skeletal anchorage devices, prompts counterclockwise rotation of the mandible. This rotation not only corrects anterior open bite but also contributes to a decrease in anterior facial height, improvements in lip incompetency, and forward movement of the chin. For successful outcomes, temporary skeletal anchorage devices, installed on both the buccal and palatal sides, must deliver equivalent intrusion force to the maxillary teeth. Treatment planning should consider factors such as skeletal discrepancies, vertical excess, incisor exposure, and configuration of the occlusal plane. Clinicians are advised to closely monitor periodontal changes and consider overcorrection to ensure lasting stability and maintenance of incisal overlap post-treatment.

Individual anatomical variability of dental arches in the period of mixed dentition with optimal occlusal ratios

Based on the results of a biometric study of plaster models of the jaws obtained in 84 children in the period of mixed dentition (8–12 years old) with a neutral location of the first permanent molars and optimal incisal overlap corresponding to the optimal functional occlusion of this age category, the main linear and angular parameters of the dental arches were determined with taking into account the trusive position of the incisors. Patients, taking into account the size of the inter-incisal angle, were divided into three groups. The first group (n=33) consisted of children with a mesotrusion position of the incisors (the value of the inter-incisor angle was 125–140°), the second group (n=27) consisted of children whose incisors were located protrusive (the value of the inter-incisor angle was less than 125°), the third group (n=24) – children with retrusion position of the incisors (the value of the inter-incisal angle is more than 140°). It has been established that in the period of mixed dentition, the main linear morphometric parameters of the dental arches are determined by the trusive types of the dental system and the vestibular-lingual inclination of the incisors. A diagnostically significant characteristic of the conjugation of the shape and size of the dental arches in the period of mixed dentition is the dental-diagonal coefficient, as the ratio of the length of the dental arch to the total component of the incisor-molar diagonals, the value of which for all types of dental systems is: for the upper jaw – 1.06 ± 0 .01; for the lower jaw – 1.09±0.01. It has been proven that in the period of mixed dentition the value of the incisal angle of the pentagon formed by the incisal diagonal and the width between the incisors is the smallest in children with protrusive incisors, while the parameters of the canine angle of the pentagon formed by the canine diagonal and the intercanine width are the largest in children with retrusion position of the incisors.

Morphometric features of dental arches in the period of mixed dentition

Based on the results of a biometric study of plaster models of the jaws obtained in 38 children in the period of early mixed dentition (8–9 years old) with a neutral location of the first permanent molars and optimal incisal overlap corresponding to the optimal functional occlusion of this age category, the limits of variability of the dental arcade index were calculated arcs with macro-, micro- and normodental type of the dental system. The total value of the width of the crowns of 12 teeth in children in the period of early mixed dentition from 92 mm to 97 mm in the upper jaw and from 85 mm to 90 mm in the lower jaw is an indicator of the normodontic type of the dental system, while the length of the dental arch is less than 92 mm in the upper jaw and 85 mm on the lower jaw indicates that such arches belong to microdont ones, and more than 97 mm on the upper jaw and 90 mm on the lower jaw – to macrodont ones. In the early period of mixed dentition, the value of the arcade index, as the ratio of the width of the dental arch to its length, in the range from 0.57 c.u. up to 0.64 c.u. is an indicator of the mesoarcade type of dental arches, and an increase (more than 0.64 a.u.) or a decrease (less than 0.57 a.u.) of this value indicates that the dental arches belong to the brachiarcade or dolichoarcade types, respectively. When constructing a dental diagnostic triangle in children with anomalies in the shape of the dental arches in the early removable dentition, it is advisable to take into account that the value of the incisor-molar diagonals is established not by determining linear parameters, but by calculating the ratio of the length of the dental arch to the value of the diagonal correction factor (upper jaw – 1 .05; lower jaw – 1.07).

Minimally Invasive Restoration of Fractured Maxillary Central Incisors with Partial Laminate Veneers- A Case Series

Porcelain laminate veneers are one of the most preferred treatment methods today, due to the increasing interest in minimally invasive approach and their superior aesthetic properties. With the appreciation of the minimally invasive approach and the developing adhesive procedures, the partial laminate veneers have become more popular in dental field. In these case series, the teeth were restored with partial laminate veneers by only intervening in the fractured area. In this case series, the teeth that were restored with partial laminate veneers were prepared with different techniques. Preparation was performed without bevel in enamel margin in the case 1, with incisal overlap and bevel to create more natural transition on tooth surface in the case 2. In the case 3, preparation with incisal overlap was performed with preparation of the palatal surface of the tooth. The optical impression was made with the digital camera of the Chairside Economical Restoration of Esthetic Ceramic (CEREC) acquisition unit (Omnicam CEREC Sirona, Bensheim, Germany), in the first case. In the other cases, impression was taken with elastomeric impression materials. In addition, restorations were fabricated from feldspathic porcelain and lithium disilicate porcelain. In all the cases, restoration was cemented with resin cements. The following cases present the minimally invasive treatment of maxillary central incisors with a partial laminate veneers fabricated from different ceramic materials. New materials, procedures, and techniques provide patients an improved quality of life and a greater self-esteem with creating a confident aesthetic smile.

ИЗМЕНЕНИЯ ЦЕФАЛОМЕТРИЧЕСКИХ ПОКАЗАТЕЛЕЙ У ДЕТЕЙ С ГЛУБОКОЙ ДИСТАЛЬНОЙ ОККЛЮЗИЕЙ

Object. A cephalometric analysis was performed in children with deep distal occlusion.&#x0D; The aim of the study — To determine the age-related changes in the vertical parameters of the face in children with deep distal occlusion.&#x0D; Methodology. The article is devoted to the analysis of cephalometric parameters in patients with deep distal occlusion at different age periods in the groups: 7-9, 10-12, 13-15 years. The calculation of 15 parameters of lateral teleroentgenograms was carried out, of which 12 characterized the vertical development of the facial skeleton and the tooth-alveolar region. The analysis was performed using a computer program for automated analysis of skull radiographs.&#x0D; Results. The study revealed age-related changes in the parameters that characterize the vertical development of the maxillofacial region in children with deep distal occlusion.&#x0D; Conclusion. Changes with age in the parameters of the angles NSL/ML, NSL/NL, anterior and posterior height of the face are early signs of a genetically determined developmental anomaly. An increase in the depth of the incisal overlap with age, a deepening of the Spee occlusal line are interrelated with an increase in the tooth-alveolar height in the incisor region and with a decrease in the tooth-alveolar height in the region of the first molars, especially in the lower jaw. The sagittal position of the upper and lower incisors in distal occlusion does not change with age and corresponds to the average normal values. Established age-related changes in the parameters of the facial skeleton in deep distal occlusion make it possible to determine the area of influence of orthodontic treatment at the stages of bite development — tooth-alveolar, in the vertical plane.

Comparison of conventional ceramic laminate veneers, partial laminate veneers and direct composite resin restorations in fracture strength after aging

ObjectivesThe objectives of this study were to test the fracture strength in vitro of laminate veneers, partial laminate veneers and composite restorations after aging and analyze the failure mode. MethodsForty extracted, sound human teeth were selected and divided into four groups: 1) Control group (CG); 2) Conventional Laminate Veneer (CLV); 3) Partial Laminate Veneer (PLV); 4) Direct Composite Resin (DCR). Laminate veneer preparations with incisal overlap were made in group CLV whereas only incisal preparations were made with a 1 mm bevel in group PLV and DCR. The indirect restorations were luted with a resin composite and the DCR group was restored with a direct resin composite restoration. The restored teeth were subsequently aged by thermocycling (20.000 cycles, 5–55 degrees C). Subsequently, the fracture strength was tested by a load to failure test at 135° on the incisal edge. A failure analysis was performed using light microscopy. The results were analyzed using Shapiro-Wilk and Kruska-Wallis test. ResultsAfter thermocycling, one sample from group CLV presented a premature adhesive failure and was excluded. Three restorations from groups PLV and DCR presented small cracks but were taken to the fracture test. After aging mean fracture load + SD (N) were: Group DCR (n = 10): 385 ± 225; Group CG (n = 10): 271 ± 100; Group PLV (n = 10): 266 ± 69; Group CLV (n = 9): 264 ± 66. Fracture strength means from groups CLV and PLV did not differ statistically from each other nor from control (p = 0.05). In the group CLV the root fracture was the most occurring fracture. In groups PLV and DCR, material cohesive failures and a mix (adhesive, tooth and material cohesive) failures were most observed. SignificanceThis in vitro study showed for the first time that partial laminate veneers can exhibit fracture strength values similar to direct composite restorations or conventional ceramic laminate veneers. All three restorative procedures presented clinically acceptable values of fracture strength. Even though three samples from groups PLV and three from DCR presented small cracks after thermocycling, these cracks do not appear to have a negative effect on the fracture strength.

Comparative characteristics of the results of facial morphometry in patients with deep incisal overlap in the treatment of bracket systems and eliners

The relevance of studying the problem of deep incisal overlap (HF) among dentofacial anomalies (CCA) is due to the high prevalence of this pathology. Among modern methods of orthodontic treatment of pathology, the use of bracket systems and aligners is highlighted. The effectiveness of these techniques can be compared in determining the morphometric characteristics obtained by tele-radiography (TEG).Material and methods. The study involved 118 people with hydraulic fracturing, the average age was 38.7 8.5 years (64 women; 54 men). The first group consisted of 49 patients who underwent correction of AFA with eliners; second, 69 patients with bracket systems. To assess the effectiveness of treatment, TRG was performed. To present the results, in the case of quantitative characteristics, the arithmetic mean of the sample value (X) and the error of the mean (m) were calculated. For qualitative signs, the frequency of the sign (%) and its standard error (m%) were calculated.Results: The values ​​of the mandibular angle (G, ArGoMe), and the angles AB / ANS (AB / SpP), APg / ANS (MM), as well as the vertical dimensions of the jaws reached values ​​characteristic of an orthognathic bite. Angle increase SNB, NSL / ML4; angle reduction ANB.Output. Elimination of a deep bite is possible both with the use of bracket systems and aligners.

Features of clinical manifestations in patients suffering from dental abnormality

Anomalies of the dentition represent one of the most common groups of pathologies in dentistry. Many complaints made by patients with dentofacial anomalies (CCA) make this problem quite relevant. In this regard, of particular interest is a more detailed study of the features of clinical manifestations in patients suffering from RF.Material and methods. The study involved 118 people with deep incisal overlap (hydraulic fracturing), the average age was 38.7 8.5 years; women accounted for 54.24%; men-45.76%. Determining the dental status for studying the clinical manifestations of abnormalities included: studying the anamnesis, patient complaints, internal and external oral examinations. When analyzing the results of the study, biostatistical methods were used.Results. An analysis of the data allows clustering of patients' complaints into the following groups: painful, functional and aesthetic. During a dental examination of patients with hydraulic fracturing, increased abrasion of the teeth, increased tone of the chewing muscles proper, and a change in the ratio of elements of the temporomandibular joint (TMJ) were visualized.Conclusions. The variety of patient complaints with this pathology indicates the relevance of this problem. Most complaints of an aesthetic nature both among women and among men are a manifestation of dissatisfaction with the appearance.

VERTICAL DIMENSION OF OCCLUSION CHARACTERISTICS IN PATIENTS WITH DIFFERENT TYPES OF MALOCCLUSIONS BY THE SHIMBASHI INDEX IN THE AGE ASPECT

Occlusal vertical dimension is one of the important parameters, which is significantly related to the functional status of the masticatory complex.&#x0D; The finding of the optimal occlusal vertical dimension and the method of its determining is a debatable and topical issue in planning of orthodontic correction and orthopedic rehabilitation.&#x0D; One of the morphometric methods of the occlusion vertical dimension (OVD) is the Shimbashi index or the LVI-index. The Shimbashi index allows us to count out the "perfect" occlusal vertical dimension due to the "golden proportion" principle based on the width of the upper center incisor.&#x0D; The purpose of the research was to verify the expediency of the Shimbashi index using while examinating orthodontic patients.&#x0D; The morphometric investigation of control-diagnostic models of jaws of 300 orthodontic patients in different ages was performed. All surveyed patients were divided into the age and the tooth row interrelation type in sagittal and vertical planes.&#x0D; In the age aspect, the smallest value of the occlusion vertical dimension is determined at the age of 8-9 years, which can be connected with incompleted stages of the bite elevation and morphofunctional formation of the masticatory complex. In the period from 8 to 11 years there is one significant increasing of the OVD, which, obviously, is connected with active growth of the alveolar processes and the realization of bite elevation stages. In the 14-15, 16-17 and 18-19 years, the OVD does not reach to the Shimbashi index value by 5 mm and it doesn’t increase more in the future.&#x0D; Among the sagittal malocclusions, the greatest vertical dimension of occlusion was observed in patients with III class of dentofacial abnormalities. This can be explained by the fact that the mesial bite is usually accompanied by an increase of vertical parameters. However, the interalveolar height was still less by 3 mm compared to the "ideal" one. In classes I and II of dentofacial abnormalities, OVD was almost the same – 13.55 ± 2.55 mm and 13.56 ± 2.55 mm, which is in average by 5 mm less (p˃0.05) than calculated one by the Shimbashi index.&#x0D; While dividing patients by the depth of the incisal overlap, we obtained quite logical results. In particular, the lowest occlusion vertical dimension was found in patients with increased depth of the incisal overlap. The most interesting is the fact that even in patients with a depth of incisor overlap less than 1/3 of the crowns of lower incisors, that is a tendency for open bite, the vertical dimension of occlusion was still less than measurement found by the Shimbashi index, although the difference between them was minimal (approximately 1,5 mm) compared to other two study groups.&#x0D; According to the results of the study, all types of malocclusions are characterized by decrease of the occlusion vertical dimension refers to the Shimbashi index. The obtained data suggest the next idea: either the occlusal vertical dimension calculated by Shimbashi index is a bit exaggerated and needs clarification, in particular by the investigation of skeletal parameters according to the skull X-ray, or, indeed, modern orthodontic patients have a total reduction of the interalveolar height.

Morphometric features of the temporomandibular joints according to MR studies in adult patients with dislocations of the articular discs and malocclusion of the anterior teeth

To study the morphological features of the temporomandibular joints (TMJ) according to MR studies in adult patients with impaired occlusion of the anterior teeth and dislocations of the articular discs. The clinical study included 51 patients aged 17 to 47 years (mean age 28.12±7.44 years): 14 men and 37 women. On the basis of a clinical examination and MR findings of TMJ in 30 patients (mean age 26.77±7.48 years; 8 men and 22 women), TMJ dysfunction in the form of dislocation of articular discs was confirmed. In 21 patients (mean age 30.05±7.12; 15 women, 6 men), TMJ dysfunction without dislocation of articular discs was confirmed. The patients measured the value of vertical incisive overlap (overbite). Analyzing data from MR studies of TMJ, we measured the following values of both TMJs of each patient: the depth and transverse size of the articular fossa, the height of the articular tubercles and the transverse size of the head of the lower jaw. The examined patients with joint dislocations of TMJ had morphological features: statistically significantly deeper and narrower articular fossae, higher articular tubercles and narrower in the sagittal plane of the head of the lower jaw compared to TMJ of patients with dysfunction without dislocation of articular disks. In addition, in patients with articular disk dislocations, a statistically significant (<0.05) increase in vertical incisal overlap was noted. .TMJ in patients with dysfunction in the form of dislocations of articular discs had morphological features that allowed them to be classified as type 3.

Analysis of the results of a clinical-dental survey of adult patients with deep overbite

The authors presented the results of a clinical and dental examination of 118 adult patients of young and middle age with deep incisal overlap. Based on the identified main types of complaints of patients with this anomaly of the maxillofacial system, their classification was carried out, gender differences of disturbing symptoms were established. Face morphometry was carried out on the basis of images obtained using lateral cephalometric radiography. Chewing function was investigated using the method of quantitative analysis of crushed particles. The results can be used for timely diagnosis and an effective treatment plan for anomalies.

Randomized clinical trial on indirect resin composite and ceramic laminate veneers: Up to 10-year findings

ObjectivesIn this randomized split-mouth clinical trial the survival rate and quality of survival of indirect resin composite and ceramic laminate veneers were evaluated. MethodsA total of 48 indirect resin composite (Estenia; n = 24) and ceramic laminate veneers (IPS Empress Esthetic; n = 24) were placed on maxillary anterior teeth. Veneer preparations with incisal overlap were performed using a mock up technique. Survival of the restoration was considered the primary outcome measure and reported using Kaplan-Meier statistics and survival curves compared by means of Log Rank (Mantel-Cox) test. After luting, restorations were evaluated by calibrated operators at baseline and every year thereafter, using modified USPHS criteria and compared by means of Mann-Whitney U test. ResultsIn total, 6 failures were observed, consisting of debonding (n = 3) and fracture (n = 3), all in the group of the indirect resin composite laminate veneers. Cumulative chance on survival after 10 years of the indirect resin composite and ceramic veneers was 75% (se 3,8%) and 100% respectively (p = 0.013). Of the surviving 42 laminate veneers, the variables ‘color match’ (p = 0.002), ‘surface roughness’ (p = 0.000), ‘fracture of the restoration’ (p = 0.028), and ‘wear of the restoration’ (p = 0.014), were significantly less favourable among the composite laminate veneers as well. ConclusionsThe ceramic veneers on maxillary anterior teeth in this study performed significantly better compared to the composite indirect laminate veneers after a decade, both in terms of survival rate and in terms of quality of the surviving restorations. Clinical RelevanceWhen indicated, anterior ceramic laminate veneers may be preferred over indirect composite laminate veneers.

Fracture Localisation of Porcelain Veneers with Different Preparation Designs.

BACKGROUND:Porcelain veneers are permanent restorations that combine good aesthetic with functionality by minimal destructive techniques.AIM:This study aimed to investigate the influence of the preparation designs on the fracture localisation.MATERIAL AND METHODS:Three preparation designs of porcelain veneers fabricated by a method of laying on a fireproof abutment on maxillary central incisor were examined in this in vitro study-feather preparation, bevel preparation and incisal overlap – palatal chamfer. The samples from all three groups were loaded into a universal test machine-TRITECH WF 10056 until damage occurred on the porcelain veneer. Fracture localisation was classified as an incisal, gingival or combination. Data were analysed with statistical programs: STATISTICA 7.1; SPSS 17.0.RESULTS:In feather preparation, as a consequence of the mechanical force, the most common is the incisal localisation (66.7%), followed by the combined (33.3%), while the gingival fracture localisation is not registered. In bevel preparation, the most common fracture localisation is combined (53.6%), followed by incisal (35.7%) and subsequent gingival localisation (10.7%). In incisal overlap (palatal chamfer), combined and gingival localisation of the fracture is equally recorded in 14.3% of the samples, while the incisal is the most common localisation and is registered in 72.4%.CONCLUSION:During the study, a statistically significant dependence was found between the localisation of the occurred changes (incisal, gingival and combination) and the three different types of preparation.

Performance of ceramic laminate veneers with immediate dentine sealing: An 11 year prospective clinical trial

ObjectiveIn this prospective clinical trial the survival, success rate and patient satisfaction of ceramic laminate veneers with special interest on existing restorations, immediate dentin sealing and endodontically treated teeth was evaluated. MethodsA total of 104 patients (mean age: 42.1 years old) received 384 feldspathic ceramic laminate veneers on maxillary anterior teeth. Veneer preparations with incisal overlap were performed using a mock up technique. Existing resin composite restorations of acceptable quality were not removed but conditioned using silica coating and silanization. Immediate dentin sealing (IDS) was applied when more than 50% of dentin was exposed during preparation. Endodontically treated teeth were not excluded. After adhesive cementation, restorations were evaluated by calibrated evaluators at baseline and final follow-up using modified USPHS criteria. Results225 Laminate veneers were bonded onto teeth without existing restorations, 159 on teeth with pre-existing resin composite restorations, 87 to teeth with more than 50% of exposed dentin surface and 43 to endodontically-treated teeth. In total, 19 failures were observed in form of debonding (n = 3), fracture (n = 15) and extraction due to endodontic complications (n = 1). In teeth with more than 50% of dentin exposure, a significant increase in survival rate was observed when IDS was used (96.4% versus 81.8%). No significant difference was found between teeth with and without pre-existing composite resin restorations (84.6% versus 95.5%) or between vital and non-vital teeth (95.6% versus 88.1%). Laminate veneers luted to endontically-treated teeth had a significant mis-match in color compared to vital teeth. Patients who smoked presented with significantly more marginal discoloration, but no intervention was needed. Patients scored favorably values on the Oral Health Impact Profile questionnaire and were generally satisfied with the treatment. In this clinical trial, the ceramic laminate veneers had a relatively high survival rate. SignificanceTeeth with more than 50% of dentin exposure significantly benefit from IDS. Pre-existing restorations or endodontic treatments do not have an effect on the survival rate of ceramic laminate veneers. However, smoking habits and previous endodontic treatments negatively affect the success rate due to color changes.Clinical Trial Registration Number: NCT03645551

The Success of Dental Veneers According To Preparation Design and Material Type.

BACKGROUND:Due to their high aesthetic outcome and long-term predictability, laminate veneers have become a common restorative procedure for anterior teeth. However, because of the variety in the preparation designs and the material types, the clinician faces a dilemma of which approach to use.AIM:To compare the survival rate of dental veneers according to different preparation designs and different material types. The sub-aim is to reach a favourable preparation design and material based on scientific evidence.METHODS:Comprehensive electronic search of the dental literature via PUBMED, MEDLINE and Scopus databases was performed using the following keywords: “porcelain veneers”, “composite veneers”, “all-ceramic veneers”, “success of porcelain veneers”, “preparation design”, “preparation geometry”, “patient’s satisfaction”. Additionally, references from the selected studies and reviews were searched for more information.RESULTS:Under the limitations of the available literature, the clinician preference is the decisive factor for choosing the preparation design. Nonetheless, incisal overlap preparation seems to have the most predictable outcome from all the preparation designs.CONCLUSION:Porcelain veneers show excellent aesthetic results and predictable longevity of the treatment, while composite veneers can be considered as a good conservative option, but with less durability.

The evaluation of stress patterns in porcelain laminate veneers with different restoration designs and loading angles induced by functional loads: A three-dimensional finite element analysis study.

Fractures in porcelain laminate veneers (PLVs) are a significant clinical problem. Preparation designs can affect stress distribution, which leads to fractures in PLVs. Therefore, identification of the most favorable preparation design in terms of stress distribution is required. The purpose of this study is to examine the functional stress patterns of PLVs with featheredge, incisal bevel, and overlapped preparation designs under 0°, 60°, and 120° functional loads using finite element analysis. Porcelain veneers with three different preparation designs (incisal overlap, incisal bevel, and featheredge) were modeled. A cement layer of 100 μm of luting composite resin was assumed, and a thickness of 0.5 mm of porcelain veneers was used. All models were loaded at 0°, 60°, and 120° to the long axis of the tooth to determine the stresses that may occur during mastication under different load angulations. A total force of 200 N was applied from the incisal edge of the models. Maximum stresses were recorded in the incisal overlapped design (53.3 MPa) under 120° of functional load. Minimum stresses were recorded in the incisal bevel preparation design (22.37 MPa) under 0° of functional load. Both the preparation design and load angle affected the stress distribution on the PLVs. The incisal bevel preparation design provided a more appropriate geometry for stress distribution compared with the other techniques. Lateral forces produced more stress on the tooth and laminate material than vertical forces.

Effect of Different Preparation Designs on the Fracture Load of Two Machinable Laminate Veneers

Aim: The present study was performed to evaluate the effect of different preparation designs [window, butt- Joint, and incisal overlap], on the fracture load of two CAD / CAM laminate veneer materials [Zirconia CAD / CAM and resinnanoceramic ; lava ultimate].Materials and Methods: Thirty maxillary anterior teeth were restored with ceramic laminate veneers and divided into 6 groups as follows: group I-A (laminates made of Ultra translucent zirconia CAD with window preparation design), group I-B (laminates made of Ultra translucent zirconia CAD with butt-joint preparation design), group I-C (laminates made of Ultra translucent zirconia CAD with incisal overlap preparation design), group II-A (laminates made of Lava ultimate (Resin nano ceramic) CAD with window preparation design), group II-B (laminates made of Lava ultimate CAD with butt-joint preparation design), group II-C (laminates made of Lava ultimate CAD with incisal overlap preparation design). Fracture load test was performed using the Universal Testing Machine (UTM). Data were statistically analyzed using One-way analysis of variance ANOVA followed by Tukey’s multiple comparisontest. The results of the fracture load test were recorded in Newton: (I-A: 288.08N);(I-B: 322.47N); (I-C: 365.38N); (II-A: 301.15N); (II-B: 324.94N); (II-C: 394.95N). The results of the current study showed that there was no statistically significant difference between the means of fracture load for window, butt-joint and incisal overlap preparation designs among zirconia material. While, there was statistically highly significant difference between the means of fracture load for window, butt-joint and incisal overlap preparation designs among Lava ultimate material. The mean of fracture load for incisal over-lap preparation design was the highest, followed by butt-joint and window designs. Nonetheless, there were no statistically significant differences between translucent zirconia and lava ultimate regarding the fracture loadamong window, butt-joint and incisal overlap preparation designs.